The dry filter-type paint spray booth is commonly used throughout the industry for touch-up spraying, batch operations and, in increasing number, as production spray booths. The filter-type booth employs a paint arrestor or filter which is constructed of paper, fiberglass or other materials and is typically mounted in a support module of the type disclosed in U.S. Pat. No. 4,693,048 issued Sep. 15, 1987 to Guetersloh and assigned to the Assignee of this application. Filters are normally 20" by 20" by 1" in size and are raised to form the front wall of an exhaust plenum which includes an exhaust fan designed to draw airborne paint particles into the filter media.
Prior art paint arrestors are comprised of a series of layers of sheet material, each of the layers being slit and expanded to define an array of generally equal sized air spaces distributing columns. Each of the layers when expanded comprises an intersecting grid pattern having runners intersecting at baffles defined by the portion of sheet material disposed between adjacent slits. Inherent to this construction is the fact that on expansion the cross-sectional area of each open air space or cell provides a capture area for a given volume of air flow having a given volume of paint particles entrained therein.
Some paint arrestors contemplate providing a plurality of plies, each parallel to the other, with the axis of the cells of one ply oriented at an oblique angle relative to the medial axis of the filter ply or run housing for defining the cell. This offset construction causes air passing through the filter media to change direction on leaving the family of cells of one ply and entering the adjacent family of cells of the next ply and encourages, thereby, the deposition of the entrained airborne materials onto the surfaces of the cells. Such an arrangement is disclosed in U.S. Pat. No. 5,252,111 issued Oct. 12, 1993 to Spencer et al.
It remains desirable to provide a system of paint arrestors for absorbing paint overspray which offers more surface area for a given product and has the ability to hold an increased amount of paint particles. Such a paint arrestor should be designed to eliminate stretch and sag when the arrestor becomes laden with paint and also to eliminate air gaps around the edges of the paint arrestor when mounted in its support module. Ideally, the paint arrestor should be manufactured with techniques which provide larger paint arrestor pads with less raw stock. It is also highly desirable to provide a paint arrestor with a high affinity to capture paint particles entrained in the fluid flow in the baffles defining the air spaces of the paint arrestor.